I don't know who should teach beginners. Years back it was much easier to figure out things when the shodan and nidans were teaching. What they were doing was generally sort of apparent. Figuring out what Sensei was doing was/is sometimes pretty tough.

My favorite classes for learning simple aikido concepts were the kids classes. For the first 6 months watching my daughters classes and listening to the explanations given to the kids really helped.

Little of what I learned as a new beginner applies to what I now think of as aikido basics. What I learned were the outer forms so that I would have some vocabulary to start learning the basics.